Come back to Cairns using the interior route, which is more scenic and diverse.
Take the main road down to the South. After Mossman, you'll see a fork in the road with Captain Cook Highway to the left and Mossman Mount Mollow Road to the right. Take Mossman Mount Mollow Road and continue on it until you come to Mount Molloy first, Quaids Dam next, and finally Mareeba. The road converges here with the A1 (Bruce Highway). Take it heading North, and you will arrive to Cairns.
If you choose this route, stop for lunch in Highlander (after Mossman, just where the curvy road ends; you can't miss it). Try their chicken schnitzel. It's delicious!
After that we recommend stopping at Mungalli Falls, which are between Millaa and Palmerston. The falls are spectacular, and in addition there are places where you can swim.
This trip takes 4 to 5 hours (including stops).