I get a very low-maintenance haircut that I can just towel, shake and finger-comb.

If I'm just stopping mid-ride, I use my skullcap to towel off sweat and then fingercomb.
If I'm stopping at work and there's no shower, I dunk my head in the restroom sink and shampoo; then towel it. After toweling it, I sometimes use Sham-Wows (or similar) to get hair from wet to almost dry.
I always wear some sort of skull cap under the helmet. It keeps the helmet cleaner, controls sweat, provides warmth in winter and shade in summer.

Nancy