There are a few options. Your hotel in Cancun can suggest a tour operator who does day tours; you can rent a car and do it on your own; or you can go on your own by bus. From the Cancun bus terminal there are first class bus departures at 5:15 am, 8 am and 9 am, it costs 144 pesos one way and takes 2 hours. Return trip at 5:10 pm. Check here for the details: www.ticketbus.com.mx