John,
A wiring diagram really is not necessary.
All that is required are normally closed switches.
Connect all the switches in series.
Connect one end of the switches to a Input Pin on the G540 connect the other end to ground on the G540.
Since Mach3 only homes one axis at a time it is aware of the which switch is tripping.
If you prefer to have each axis separate then you can wire the switches on each axis in series and use one Input pin for each axis.
Using one input pin for all the Home and Limit switches will conserve the other inputs for accessories.
Jeff...
Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.