As Neil says, unfortunately there is no definitive colour coding for pads, though there are often similarities between manufacturers and often for instance, finishing pads will be black, but it does vary so not reliable to assume they will be the same.
The more open cell and firmer the foam, the more cut it has. The more closed cell and softer the foam, the less cut. You should be able to tell cutting or polishing pads from finishing pads this way.
It's really quite important to get into a good care regime for your pads, and best to wash and dry them after each use. I wash mine (foam and microfibre pads) in the machine at 30°C (non bio liquid) and air dry, but you can wash them by hand with some washing up liquid, rinse and squeeze out, the dry. Good idea is to store individually in labelled plastic sandwich bags to keep dust off and/or in a lidded container.