OK, I scanned in the three wiring diagrams I have.
>The first one is a generic drawing that applies to most machines. It's fairly easy to follow. If you refer to it when you look at the two Singer diagrams it might help.
>The second one is the diagram to the 221 series machines. It shows how the block on the machine and the cord is wired. The biggest difference between the 221 and other Singers is the 221 has a separate switch between the block and the light. Most other Singers have the switch at the light. The cord side will be the same.
>The third picture show the different ways Singer wired the machines. The top motor is like yours. All the wires go to a separate two piece junction block. The bottom motor does not have a junction block, all it's wires are hard wired together with screw connectors.
The thing is, all the circuits shown in these drawings are the same. It's easier to understand if you print out the drawings and put them right next to your actual wiring project.