What colour was the first man on earth?

What we refer to as "Color" (capitalized) is a modern convention. The first human ("Man" vs. "man")would have been multicolored. The references to "White" "Red" "Black" "Yellow" as an ethnic identity are human conventions, not physical traits. The concept of first "human" is by itself a spectrum of evolution, and where one chooses to select a point along the spectrum is a matter of personal choice. The question lacks context.