The colour bands are artifacts of the camera lenses and housing. From the wikipedia article[1]:
The result of the brightness is a bright burned-out image with multiple reflections from the optics in the camera. The rays around the sun are a diffraction pattern of the calibration lamp which is mounted in front of the wide-angle lens. [..] In the photograph, Earth lies in the center of one of the scattered light rays resulting from taking the image with a small angle between the Sun and the Earth
The result of the brightness is a bright burned-out image with multiple reflections from the optics in the camera. The rays around the sun are a diffraction pattern of the calibration lamp which is mounted in front of the wide-angle lens. [..] In the photograph, Earth lies in the center of one of the scattered light rays resulting from taking the image with a small angle between the Sun and the Earth
The following picture demonstrates the relative position of the sun and the Earth: https://en.wikipedia.org/wiki/File:Solar_System_Portrait_-_V...
[1]: https://en.wikipedia.org/wiki/Pale_Blue_Dot#Camera