You would be better served posing this question to our friends at /r/AskAnthropology, as this isn't really a question suited to historical studies.

The amount of hair we think they had changed since the XIX century, when scientifics representate them more related to monkeys than to actual humans. Now we know that this wasn't true, so we can representate them more accurately. Also, knowing their DNA helps to find where they habitated, other way to guess how they looked. I can put some bibliography if needed, but I'm not english so you probably can't read them. Just search in Google for old and actual pictures of them so you can compare.