The Buddha was not ‘into’ hair. He asked his monks and nuns to shave their hair every two months or when it was two finger-breadth long (Vin.II,207). Nuns were expected to shave their pubic hair which apparently all respectable women did (Vin.III,260). Monks were also asked to cut the hair in their noses if it got too long (Vin.II,134). Statues of the Buddha always show him with hair but of course he shaved his head like all other monks.
We have quite a lot of information about the hair styles of the time and this is supplemented by archaeological evidence. Certain ascetics wore jatas, what we call dreadlocks, i.e. the hair was matted into long braids and then allowed to either hang down or be tied together into various shapes. When the braids were tied into a bun on the top of the head it was called jatanduva (S.I,117). Centuries later Siva and Avalokitesvara were always depicted with their hair like this. Brahman men probably shaved their heads except for a small part at the back which was left to keep growing, just as they still do. Topknots or buns on the back or top of the head were also popular. Another type of topknot was the culaka. Boys would wear five of these (Ja.V,250) and women would sometimes have a jeweled diadem attached to theirs (Ja.I,65). Sikhabandha seems to have meant twisting long hair and a long cloth together and then tying it around the head into a turban (D.I,7). Women favored parting their hair in the middle (dvedhasira vibhatta) as they still do, wearing plats (veni, Ja.II,185) and applying sandal oil to their hair both to perfume it and make it glisten (Ja.V,156). The high-class prostitute Ambapali used to wear her hair glossy-black, curled at the ends, with flowers in it, well-parted with a comb, decorated with gold ornaments and adorned with plats (Thi.252-5). When Nanda left to become a monk, he looked back and saw his girlfriend with her ‘hair half combed’ (upaddhullikhitehi kesehi), an image that later he couldn’t get out of his mind (Ud.22). Perhaps it was something like in those shampoo ads where you see the woman’s hair blowing in the wind.
Bees’ wax was applied to slick the hair down (Vin.II,207) and later Indian works mention that the sap of the banyan tree was used as a sort of hair gel. Men trimmed their beards, grew them long, grew goatees (golomikam karapenti), and shaped them into four ends. They would sometimes shave shapes into the hair on their chest and abdomen or even have all their body hair removed (Vin.II,134). There were hairdressers (kappaka) and barbers (nahapita) to do all his coffering and the second of these usually doubled as bath attendants and masseurs. Just as today, both professions attracted homosexuals, as the Kama Sutra makes clear. The barber’s equipment (khurabandana) would include a razor (khura), scissors (kattarika), tweezers (sandasa), comb (koccha) and mirror (dasa).
The two pictures below, both of sculptures from Bharhut (150-100 BCE) throw more light on ancient Indian hairstyles. In the first the two women with their backs to the viewer showing their hair platted into numerous braids and then all of them tied into a single knot. The bottom picture shows a man arranging his turban (and hair?).