The large cruise ships dock at Trinity Wharf which is a short walk to the middle of town. There's really nothing much to see in Cairns itself. It's full of cheap restaurants and tacky souvenir shops which has seen better days due to fewer tourists arriving.

People who go to Cairns do so because of the Great Barrier Reef. It would make for a great day trip if you have the time. The tours to GBR leave at around 8am and come back around 4:30PM. Another possibility would be to go to Kuranda/Tjapukai...could be done in as short as half a day.