@old_no7 Using the colors of the map you linked, I don’t know why HBG wouldn’t work for you. No, they don’t pay me anything. But, to me, it’s the obvious solution. So I wonder why it would not work for you…
Here’s what I would buy, with links to the correct pages:
First, the All-Allied look:
French Dark Blue
China Light Green
British Tan
(potentially US Green)
(potentially USSR Brown)
https://www.historicalboardgaming.com/Battle-Pieces--Allies--Mack-Truck-x5_p_1164.html
French in Blue (can also use Dark Green here for US)
China in either Light Green or Celery Green (Light Green will probably work better)
Brits in Tan
(can also use Dark Green here for US)
(can also also use Brown here for USSR)
This would also help with piece recognition - all the trucks on the Allied side would look alike. Some more national solutions for the Brits, the US, and the USSR follow:
Brits can also do
https://www.historicalboardgaming.com/Battle-Pieces--UK-Supp--Kangaroo-Mech-Infantry-x5_p_1888.html
in Tan or ANZAC Grey (Tan is probably best here)
US Dark Green -
https://www.historicalboardgaming.com/Battle-Pieces--US-Exp--M3A2-Halftrack-x5_p_2080.html
in Dark Green
USSR Brown
https://www.historicalboardgaming.com/Battle-Pieces--Russia-Early-War--Gaz-60-Mechanized-Infantry-x5_p_1143.html
in Brown (Russia)
Now, the Axis. Doing the Allies in trucks and the Axis in Half-tracks will help tell them apart:
German Grey - either
https://www.historicalboardgaming.com/Battle-Pieces--Axis-Minors--Opel-Maultier-Truck-x5_p_781.html
in Light Grey
or
https://www.historicalboardgaming.com/Battle-Pieces--German-Exp--Halftrack-Mechanized-2501-x5_p_2170.html
in Dark Grey
Japan Yellow
https://www.historicalboardgaming.com/Battle-Pieces--Japanese-Supp--Type-1-Ho-Ha-Mech-x5_p_1620.html
in Yellow Gold
And last, our neutral nations (assuming you want to get them half-tracks / trucks as well)
Neutral Light Tan
https://www.historicalboardgaming.com/Battle-Pieces--Neutrals--Polish-Truck-x5_p_790.html
in Blonde
Again, if you want an exact color match, you will need to paint. But I think these are close to what you are asking for.
If the above does not help, please be more specific.
My 2 IPCs,
-Midnight_Reaper