"What is the relevance of the red/yellow/white colour of the arrows in your CoF diagrams and how do they relate to the fretboard diagrams?"

The white arrows represent nothing as they are part of the circle of fifths.

There are two types of modes, parallel and relative. If we focus on the note "A," for example, it's in the keys that are represented by the yellow arrows.

The yellow arrows are parallel modes.

Modes are always in the following order: Ionion Dorian Phrygian Lydian Mixolydian Aeolian Locrian

There are 7 of them. Accordingly there are 7 yellow arrows.

The red arrow is the key that the mode is derived from. If the red arrow is on the key of "E". Then A is the 4th mode of E. E F# G# A

Therefore, A Lydian is derived from the key of "E"

The fretboard diagram is self explanatory IMHO. I thought I did a pretty good job at explaining how the scale patterns move from string to string in Chart 1. But, if you need help with it - ask.