it is called "rainbow piano" C-red D-orange E-yellow F- green G-aqua A- Dk Blue B-purple

There is a piano pedagogy method known as the "Rainbow Piano Technique" that assigns colors to different notes on the keyboard.

This color code includes a large number of distinct colors which are assigned to notes spanning a little more than 3 octave, including selected accidentals. Colors are not repeated at the octave. Color tags are meant to be taped to your keyboard.

The method then uses special scores with noteheads that are colored to correspond to the colored tags on the keyboard.