Two outputs for water - left and right. One for cooler water than than the other.
Two buttons to press - top and bottom.
The assumptive link here is that we tend to work left to right and top to bottom, so logically the top button produces water from the left side. But we do need to explicitly think about this and check ourselves. Maybe that's why there's a wet floor as people do get it wrong, and enter health and safety considerations and hence the sign. Water's no only a precious resource but costs money too, so no real excuse to be less than really clear. Wonder how many people get cold when they want regular and then vise vera and end up wasting.
Why not just put the buttons side by side, even some labels might help.
