Donovan later re-recorded the song with a band arrangement; that's the one in the sound clip. The original was just him and a guitar.

The song gets asked about here from time to time. Usually somebody insists on posting a parody, though that wears thin quite quickly. See also

colours by donovan

colors donovan

Red is the Color of My True Love's H

Colors (Digital Tradition file with title mis-spelled and incomplete attribution)