There are a few ways that a person's hair can interact with various kinks and fetishes. People are often drawn to bright peroxide blonde hair, for example, while a lot of people find redheads instinctively attractive. Submissives into femdoms might look out for dark, glossy brunettes, while unnatural dyed colours can be appealing in age play or cg/l circles. Then there's hairstyle: pigtails, shaved heads and more unusual cuts have all been involved in a variety of fetishes before now!
The most important thing of all, of course, is not to let your partner pressure you into changing your appearance in ways you're not happy with. If the thought of having them pick a hairstyle or dye colour for you fits in with how you want to do BDSM, then that's great - but if not, don't feel you need to change yourself just to please them.