The tethers look different in shape.
blue-white is less twisted, ribbon
red-green is more like a DNA strand.

put up markers for tanks, melee, and ranged ppl, in a triangle shape.
there's always 2 pairs, and it's always 2 melee, 2 ranged/casters, 2 tanks; so to prepare, you always stand with the ppl you can be paired with; away from other groups.
if it's a tank-melee combo, the melees move behind the boss, so you don't get to close to tanks, and begin gaining stacks. then you rotate in the same direction, to avoid cone-aoes
if it's a melee-ranged combo, you stand left and right of boss; away from each other, and rotate in same directions, to avoid aoes.
so you don't even need to use color, to distinguish them; you don't even need to look at the shapes, you just need to look at what group has tethers.