Trust me (speaking from experience here), because you only got 4 hours sleep yesterday, Don't do an all-nighter as your brain won't function properly and you won't be able to think properly enough to answer the questions accurately/ get good marks
using past papers/ tsr, try and predict what will come up and revise that as much as possible- (but still revise everything broadly). I'd also just do 1 past paper to make sure you're used to the timing/ layout- which will prepare your brain for the exam
and get like 4(or more-if you can) hours sleep today
and don't have caffeine as it's a diuretic, it'll just make you want to pee badly in the exam which will hinder your performance (unless you know exactly how your body responds to caffeine)