Latex mattresses are made with an open-cell structure, which provides much better airflow than memory foam. 
On top of that, latex mattresses are designed with breathable pinholes throughout the mattress, which creates much better circulation.
Take a look below:
That being said, a latex mattress isn’t necessarily going to provide you with a cool sleep.
A latex mattress is still made up of a foam block, which doesn’t offer the best ventilation possible.
If you’re a naturally hot sleeper, the coolest latex option would be a hybrid latex mattress with pocket springs.
The gaps between the springs will allow excess heat to draw out underneath the mattress.