Modern native European genetics can be roughly said to derive from 3 main sources. One is western Hunter gatherer (WHG). These were not the first people in Europe but were the first to populate Europe after the latest ice age ended. By analysing their genome we think they were dark skinned, black haired and had blue eyes. The light skin adaptation didn’t actually develop in Europe but in the middle east. Here is where the second group comes from.

Early European Farmer (EEF) originally came from Anatolia and were the ones spreading farming around Europe. Interestingly the spread of farming was not spread by knowledge transfer but by the migration and expansion of EEFs. The EEFs and the WHGs would coexist for hundreds of years with little admixture, living completely different lifestyles. The early European farmers, whose genetics derive from Neolithic Anatolia, were light skinned, brown eyed and relatively short. Modern groups with the most genetic similarity to EEFs are modern day Sicilians so you can imagine that. Overtime the EEFs and the WHGs would eventually mix however.

The third group are the yamnaya, also called steppe Ancestry. The yamnaya were a people group in modern day Romania and Ukraine who just so happened to invent the concept of riding a horse and after they did so they steamrolled about all of Europe in aggressive conquest. The Indo European languages derived from them and their expansion vastly changed the genetics of the continent. And all Europeans derive at least part of their genetics from them, of course in different amounts depending on the region. They were believed to be quite tall and have blond hair and are the “Aryans” that the Nazis talked about.

All modern Europeans are a mixture of these 3 groups, in different proportions. So returning to the pictures in the OP it makes sense for the cheddar man would be dark skinned as he would be 100% WHG as he lives way before any of these groups moved in. This does not mean however that the guy on the right is not a direct ancestor, he very well may be. But since he is also a result of the later migrants, the EEFs and the Indo European expansion, he will of course look vastly different.