Normally the riddle with the four orb colors is very simple and would be a waste of a riddle key, since people can "cheat" by writing down the colors shown until they have the right combination.
Would it help if instead of one colored orb appearing, I would show the four orbs side by side and flash them in the order in which you need to interact with them? Or is the flashing hard to see as well?
What other riddles on the brexeet isles cause you problems due to the colors?
Sadly there is no simple way to retroactively add a colorblind mode to the game, since it's not an option in the rpg maker, and some stuff in the game requires colors in the riddles or in the desciptions in quests or dialogs.