From the official site:

"There will be five different designs for each of these forms for the Horde and Alliance. Night elves can choose to change their cat and bear look at any time by visiting the barber shop and changing their character's hair color, while tauren will be able to change which look they use by switching skin tones in the barber shop -- a new feature for tauren in the next major content patch. Given that there are more hair colors and skin tones than unique form looks, some colors and tones will overlap with these new textures. The hair and skin colors chosen will, in most cases, correspond with the color seen in the look of each form. Some similar colors that may share a particular cat texture will not necessarily share the same bear texture. "