one of the jacks will be a stereo type so the battery can be switched in/out of circuit when the guitar jack is inserted (typically the input).
you just miss out the battery, led & resistor if you don't want to use 'em - you can also use a DPDT footswitch that way too. the diagram as show requires a 3PDT footswitch which are a bit harder to get here in the UK.
:twisted: