The Chinese do have 56 different ethnic groups which make up their population. Some of them are very much Caucasian or at least Middle Eastern as I myself saw. Their Muslim populations are a mix of Central Asian, Han Chinese, Persian and other lineages. I saw people that, if I had seen them on the streets of the U.S., I would never have thought they were Chinese.
But Qin Shi Huang I believe was very “Chinese-looking”. Every indication is that he would have been black-haired, dark-eyed and “yellow”-skinned (as the Chinese style themselves. All the ancient depictions of him that I’m aware of have him as such.