My first thought was just to chill until they bring you down to cook you, then start with the surprise headbutts, because you're mighty and they're hungry and weak, ya just knock 'em down one by one. Maybe eat THEM just to make a point.
But then I think if they're leaving you to hang overnight, they couldn't be THAT starved - and not so weak. So I wonder, how many of them are there? How many cannibals does one person feed?
Well, waiting to be brought down won't work because they could just kill you where you hang before cooking breakfast. To swing up would be noisy, with them sleeping right underneath, better hope they're heavy sleepers. It could be possible to climb the rope even with bound hands, being mighty athletic.
Once upon the branch, it depends how the rope is attached to the branch, if it's tied directly to the branch it could be possible to just slide the rope off as the branch narrows. If the rope is tied by the ground and slung over the branch (more likely), then you've got a lot of rope to work with once you jump to the ground.
So before jumping to the ground, find something sharp amongst the cannibals because you'll have to quickly cut yourself free after jumping (it'll be loud and they'll wake up, maybe jump ON the strongest cannibal). Best to wait until late in the night, when they'll be in a deeper sleep so it'll take longer for them to figure out what's going on.
If you've made it this far, you're free from the rope and now have a sharp weapon. Congratulation! Because you're mighty, you now have the choice to run away, or maybe kill some of them and become the brutal new leader...
(The choice is obvious, how many people get a chance to lead a tribe of cannibals?!)