Hair Salon Tipping Question?

I'm a guy and I went to a hair salon for the first time and I wasn't sure how tipping worked. Usually I go to a barber shop and when you are done with your haircut the person who cuts your hair goes to the register and collects the payment and you tip them there. At the hair salon (Toni and Guy), the guy who cut my hair just walked off after he was done and I went and paid for the haircut and had to go and give him his tip so I was a little confused. Was I not supposed to tip him or what?