View | Axes
This command enables current co-ordinate system axes to be viewed in viewer window.

1. Click View | Axes.

It pops up Axis Dialog box  which contains a slider to modify the size or length of axis vector and show/hide check box..

Short Cut : a (Toggle key)

The triad has three color axes. X, Y and Z axes are referred in Red, Green and Blue  colors respectively.

2. Close Axis dialog box.