Unfortunately, there is no standardization. To my knowledge, there are only two major companies that produce sabots - MMP and Harvester. The only two colors that are basically standard are black and green, I think. And, the color schemes can go out the window when those two make sabots for Hornady, Barnes, TC, etc. Each company specifies the color they want for a particular sku.
MMP
.58
Gray .58/.45
.54
White .54/.429
Red .54/.45
Purple .54/.50
.50
Orange .50.458
Black .50/.45
Green .50/.429
Dk Blu .50/.40
.45
Tan .45/.40
Lt Blue .45/.40
Dk Blu .45/.357
Harvester
.54
Red .54/.45
.50
Black .50/.45
Red .50/.45 (high pressure)
Green .50/.429
Lt blu .50/.475
.45
Lt Blu .45/.40