That appears to be a 10-turn pot, and the left pin is marked "CW" on the case, so turning the screw clockwise will decrease the resistance between the left and center terminals. In this case, because of the screw mechanism, you can't really visualize the relation between the terminals, resistance element, and screw rotation.
This one is a single-turn pot, and the right terminal will be the clockwise end of the element. With this design, the resistance element is a semi-circle with a gap at the bottom. The two end terminals can be easily visualised as the CCW (left) and CW (right) ends of the resistance element, and the center terminal goes up through the gap in the element to connect to the moving terminal.