There’s probably an easy way to pass your own palette, as Jules suggested. You may want to look into that. Maybe package ColorSchemes works out of the box (it works great with simple Plots situations I’ve tried).
Here’s an issue I’ve made, hopefully some experts will weigh in: https://github.com/JuliaPlots/AlgebraOfGraphics.jl/issues/245
Just for the record, here’s a related discussion: Coloring boxplot groups in Makie