The pigtail is not a factory installed option. Thus, it will not show on any of the schematics.
Many dealers add this to their bikes before the sale, but, it is done strictly on a dealer to dealer basis.
Many do not choose to provide it.
The pigtail wires straight to the battery......red on + and black on -
Some of the pigtails are green and yellow, If I remember right....if so, the yellow is + and the green-
Hoop...trace your wires back and see where they go.