I found this website with some good pictures and even some instructions.
https://learn.sparkfun.com/tutorials...ical-connector I would use the 2-ended red connector shown on this page, which you can get at the hardware store or Radio Shack. Cut out the chewed section of wire, strip about 1/4" of insulation from each end. Put a wire in each end, and crimp. You could add some electrical tape for good measure. Then you'll be back in business!