You can use the Xilinx cable with Altera devices, if the Xilinx programming tool (or any other tool operational with the cable) will support a portable programming file, e.g. STAPL (Standard Test and Programming Language) or SVF (Serial Vector Format), that can be generated directly or indirectly (by conversion tools) from the Altera programming files. I know, that e.g. Lattice ispVM System is good in integrating 3rd party programming files, but I don't about Xilinx. Your surely can't use the Xilinx cable with Altera tools (unless you manage to write a bridging driver, good luck).