From what I remember
In the good old days before a black board became a chalk board the colours were:-
Axis: white - drawn thinly
Blade: white
IAF: Green ( you knew that one!!!)
RAF: red
Tq: brown
Lift: yellow - drawn thinly
Drag: yellow - drawn thinly
TR: Purpled
TRT: thick white for emphasis
Wt: thick white for emphasis
Auto Rotative Force: yellow
Rate of descent flow: Blue
You were limited by the amount of colours of chalk. When the magi-board came along white became black but the key colours remained the same.
That was a trip down memory lane - better sit down
