Connect Macbook Pro to DacMagic DAC

What is the best cable option to comnect my Apple Macbook Pro to my DacMagic DAC? The usb cable provided by Cambridge works okay but can't I get better sound using a mini-rca from the Mac's headphone jack and running it into the DAC's Toslink input? Or, is there such a thing as a mini-rca to coaxial spdif cable? What is the best cable you've ever used for this application?
I've been very happy with my Wireworld Supernova 6-mini. I use it to connect my Macbook Pro, running Pure Music Software, to a Bryston BDA-1 DAC.
As kind of an aside, the DACMagic + has a USB / BlueTooth dongle which makes a wireless connection without using such as an AirPort Express. Or an optical cable.