I could, but not with pictures anymore as I have it already installed in the game. Basically you wire up all the LED's with 2 wires. Run them to the back however you like. I ran them along the sides of the clear playfield, but you could just go straight down and under like Hemi does.
now for the diode board you could use a breadboard. I didn't have any breadboard sitting around anymore, but I have piles of 555 socket under playfield lamp boards. Took one with 4 bulbs on it, since they have the diodes and plug already there.
but if you were to make it with a breadboard. You need 3, sets of 5 pin board molex mounting pins. 2 on one side. and one for the other side (your Z plug has 2 molex connectors) One for the current 4 bulb plug, and one for the new 5 pin plug your going to be making with your 4 LEDS. (other side has your plug that goes to the boards). Run one wire from each LED, to the plug in order. 1,2,3,4 and 5 is the common. All 4 of the second wires are bunched together in put on the last pin. Wire up both board plugs so they are jumpered together. Pin 1 goes to pin 1 on the second plug, and 2 to 2 and so on. Then have 4 diodes mounted to the board, with the banded side going towards the bulbs/LEDs. Connect the other side to the plug on the opposite side of the board, where your other molex that goes to the boards connects. That's pretty much it.