We don't generally use colour for specific documents, and I would say that it is probably not a good idea unless it is really necessary, for what I call at a glance.
Examples could be if you require multiple documents at a work station but the documents are very different and "at a glance" is required to distinguish between these very important documents. For example, a station that deals with multiple parts or assemblies, each could be colour coded and have work instructions or procedures on the corresponding paper.
OR if you require prioritisation of documents in when they need dealing with. BUT nowadays you should be looking to REDUCE the paper you use, not increase the amount of different types you use. THINK, the more different colours you need the more paper you need to buy!
Anyway, I have one instance where the colour of the paper has improved the process. Our engineering release system is still circulated paper based (I am going to change this when I get a chance!), and the white paper kept getting lost on peoples desks amongst all the other piles!
So I stipulated that all Engineering releases are done on luminous yellow paper and we have not lost one yet!!! So bright colours are good for documents people just shove in there piles!