This stunning image, captured by the NASA/ESA Hubble Space Telescope shows part of the sky in the constellation of Sagittarius (The Archer). While some of the colours in this frame have been enhanced and tweaked during the process of creating the image from the observational data, different stars do indeed glow in different colours. Stars differ in colour according to their surface temperature: very hot stars are blue or white, while cooler stars are redder.
See http://www.spacetelescope.org/images/potw1703a/
