Check eBay. People part out Electrolux canisters on there all the time. Also, be sure to cast a wide enough net to encompass other Electrolux models that might use the same switch.
I've never had one of the older style canisters, much less had one apart, but the switches on the 1205-style square metal canisters are actually a two-piece affair. There's the plastic rocker, which covers the actual switch. Carefully examine the rocker to ensure no little pieces of plastic are broken off, then examine the switch. If it moves with no resistance and you don't feel a little 'click', chances are it is worn out and needs replacing. This actually may work to your advantage as you may be able to find a generic switch the same size and shape to replace it.
Assuming the Model G is set up like the 1205 and its immediate descendants, the switch will be mounted on a metal plate with rivets, which you'll need to grind or drill away, then mount the new switch in its place.