Typical lathe set up.
Typical for a rear tool post/turret lathe.
Towards the operator or away from the operator is irrelevant. Why is this? Because you have front and rear turrets. Which way the tool is moving in relation to its start position and center of spindle is what matters. From larger diameter to smaller diameter is a move in the negative direction.
Be sure to read the Newfangled Lathe Turret Standard.pdf in your Mach4/Docs folder.
Mach is smart enough to look at tool offset, Tip dir and Direction of that tool offset when executing Gcode to determine which way a + or - move needs to move the tool. Jogging is a little different though. Jogging is a manual operation and Mach does not try to determine which way is a + or - move for any given tool. It just jogs in one of 2 directions at the operators discretion. The screen layout follows the right hand rule of other default machine types and some lathes, so it is the most common. That's not to say it couldn't be optimized for others though. Some will want the X jog buttons to be the exact opposite of what they are by default. Others with 2 turrets may just get rid of the + and - signs all together.