I'm not sure about these days, but back when I was a young punk kid in my 30s "you guys" was common for both sexes. Sometimes women would only use it for other women but I've heard it used in reference to mixed sex groups. One of my favorite quotes was from someone who didn't accept use of the phrase in reference to females who quoted someone who did use it for females saying, "I've even heard guys use it that way!" Somehow he thought he had scored some kind of a coup.