Hi all, new here and not very technological so be gentle.

I have bought an old Optiplex 380 SFF to use for a homemade arcade cabinet project and need some wiring advice / help. Basically I want to add and illuminated arcade button to act as the power switch when the cabinet is built as the computer will be inside and not accessible.  As these computers do not have traditional headers / pins for the power switch I am stuck as how to achieve this. Looking at it I believe that the ribbon connector that connects the power audio USB front panel to the motherboard would be a good place to look, dell part number UM941. Ideally I would like to isolate the + and - for both the power switch and the power led within this ribbon. Does anyone have a wiring diagram for this part number? Or a pinout for the motherboard and the front panel? Motherboard part number is R64DJ and front panel is XW055

Thanks