All the 6 quarks come in 3 colors, or flavours, red, green and blue.
The antiparticles have been assigned the “anti” color, based on an additive color system, cyan, magenta and yellow. In addition to the color change, the transparency/opacity of the colored surfaces of the particle has been reversed. The inverted transparency is to accommodate the colorless particles such as the most of the bosons and the leptons.
Since Up and Down Quarks both are 1st generation particles, but with different mass, they have been given the same number of geometric elements, just inverted in positive and negative space.