Cat5 and Cat6 work for high speed data transfer because the electrical relationship between all the pairs is consistently maintained . Each pair has a specific function, and the # of twists per foot, the capacitance between conductors and between pairs is very carefully engineered for minimal loss at the high frequencies needed for data. That said, you could use 4 pairs of audio cable to act as data cable, but why would you? It won't work for long distances and will cost a lot more. If you want to use Cat5/6 to carry audio signals, note that the individual pairs of cat 5/6 are not shielded from each other, so the possibility of crosstalk between pairs is high, and with no shield, your signal is susceptible to EMI and RF noise. If your system requires cat5/6, buy good quality pre-made certified cables at whatever length you need. That way you are guaranteed that they will work. You could buy a decent cat5/6 crimper and ends, and with a little practice, get good at crimping rj45 connectors on, but a lot of times, the transport protocols are very finicky, and unless you maintain perfect distance between pairs when crimping, even though all your wires are in the right location in the connector, it still might not work, especially at longer distances. My advice... if it is shorter lengths, under 50ft, and you need cat6, get premade cat6 cables from monoprice, don't buy the cheapest ones they make, don't buy stupid extra gold plated nonsense cables either. You are thinking too hard. just get what the system asks for.
You need to make a snake? Contact a cable assembly house, like Clark Wire and Cable, in Illinois, they can make a snake for you, put it all under techflex, terminate the ends and test with a proper network tester to guarantee it will perform to cat 5 or cat 6 specs.
To do it yourself buy a roll of cat 6, cat 6 versions of RJ45 connectors (NOT the EZ45's that poke the cable through the front of the connector, they rarely work at high speeds), and a crimper made specifically for cat 6, and get yourself a little cat5/6 continuity tester, that way you can be sure all wires at both end are in the right spot in the connector and passing signal. This won't test with actual data but if you are somewhat careful when crimping it should be good enough. you are not sending data through this assembly at 10Gb/sec, so the cable doesn't need to be perfect.