firstly great mod, always wanted to have the gas generator as an standalone mod so thank you for that!

why did you choose do deviate from vanilla factorio color upgrade sheme (yellow>red>blue>green) to this ?
I am not saying you should change it to vanilla, just curious why you chose do deviate?

I too was looking for a gas generator mod and found the one from midnightxrush. He set the colors to what they are now.
Also there isn't a vanilla sheme in general. Belts use yellow>red>blue while assemblers use grey>green>blue (there was an unused red assembler back in the days) and grey>yellow>blue>green for inserters.

I'll add an option to set a color sheme but im not shure if i have the time today.