How is a display with colored cylinders instead of flip-discs / flip-dots called?
My company uses something similar as an indicator. The flip disc has a magnet in it, and one side is brightly colored while the other is black. Current is directed through an electromagnet just behind the disc briefly, one way, to align the magnetic fields and get the brightly colored side to flip forward. When current flows the other way, the magnetic field flips, as does the disc, and the black side shows.

The discs themselves are mechanically designed so that a quick magnetic burst will flip them, and they stay in a mechanically stable state so that you don't have to continuously apply current to the electromagnet to keep them in place.

Our 'discs' are basically small cylinders. To answer your actual question, they are called "flylinder".