There are two separate issues here:
- "Distance identification" - being able to identify from a distance which cable is being used. Usually related to sitting at the FoH mix position and trying to work out which mic the singer has lifted this time...
Using tape of differing colours may seems like a good idea at first, but is effectively useless in many lighting environments. However, colour is often useful for indicating cable lengths.
- "End Identification" and "Ownership Identification". When confronted with a bunch of cable ends, it is useful to be able to easily identify each cable. A simple numbering scheme may suffice, or a more complex scheme with a "serial number" and date for each cable may be appropriate.
An indication of the cable ownership is also useful, otherwise XLRs have a habit of disappearing into other people's gig bags.
While simple marking with a Sharpie or paint may suffice, a more professional effect can be obtained by using a label printer such as a P-Touch or similar. In some situations, a layer of clear Heat Shrink over the label will make it more secure and permanent.
If cables are being purchased in bulk, it may be possible to arrange for the owner's name to be printed along the length of the cable.