Kinda hard to tell from the little bit you shared here. It could just be a nervous habit or some shy playfulness to see if you react. Either way, and assuming dating among the workforce is okay, ask her out. Who cares if she has beautiful hair or not (you know what I mean), just chat with her. Let's face it, if dating among the workforce is against the rules, beautiful hair or not, you would likely find yourself on the wrong end of the rules if you start to "hit" on her for her hair.

I don't know how old you are (or she) but I'm going to guess at least your mid to late 20's. You both should be smart enough to realize the reason someone starts to chat with, and ask out, someone is because their is an unspoken physical attraction. Save the "you have (a) beautiful..." for the second or third date. She already knows that you find her attractive for some reason, that is why you asked her out.

Best of luck and keep us posted.