Best evidence out there shows that there was no single skin color and that variety was far more localized than previously thought.
Listen, it comes down to isolation. Early peoples tended to be very localized once they moved into an area, with very little outbreeding for extended periods. Breeding was likely to be in overlapping circles, with several smaller groups within a range of the target group. Those smaller groups had their own circle range...etc. It made localized superficial evolutionary changes rather rapid.
Hair, skin, and eye changes are super fast in genetic terms. They change quicker than just about everything else. Even fingernail changes are slower than those three.
It's very likely that skin tone was actually a very late developer in the first place in terms of humans overall, but once it did, it was constantly on the move.
Many IE peoples were what we *might* call dark skinned, but many were also light, and they shifted as time changed the environment they lived in. Think Indian subcontinent, Native America (startling range within those groups), and the Middle East (more startling ranges).
The rule of thumb is that the longer an environment is low in shortwave radiation, the lighter the skin gets. The longer an environment is high in reflective surfaces, the lighter the eyes get. The colder an environment comes, the thicker and more grease retaining hair gets, as well as greater levels of body and face hair.
So, while Cheddar man is an interesting subject, he's not the end-all, be all of skin. Given that environment at that time during that particular climate, one might expect a person with moderately brown and easily tanned skin, light eyes, and thick hair that lays somewhat flat to the head.