That seems to be a generic Cole Hersee ignition switch, so no use to repair it (usually it's the brass key that gets worn).
This is what the OE switch for a very early J4 looks like from the back together with its wiring -
To be fair, the diagram posted is not that unhelpful. It just needs to be read and some effort is needed by the OP. According to the diagram, the IGN wire goes to the coil.
To be fair, this is a much later switch than the one applicable a '62 FJ40 with a generator and this posted style can...