Axis labelling can be however you want.

The convention is:
Standing in front of machine (as you will actually be using it)
Left to right is X
Front to back is Y
Up and down is Z

So yes like a graph.
CAD and CAM software is based on / defaults to this convention, so easiest to follow it.

Some people get funny and insist that across the gantry must be Y. Or the longest axis must be X. They are wrong. It's about how you draw the design / do the CAM.