If you are printing to it wirelessly you don't need the USB cable connected at all.
You only need to connect the USB cable when you are installing the Canon printer driver software.
If you haven't already set up your printer for wireless printing, you first need to go into the printer's setup menu on the printer itself, go into wireless setup, then look for the network name (SSID) of your wireless router and select that.
Now enter the wireless key relating to that router.
When your laptop is connected wirelessly to the router, you should see the printer by name when you click "Print" in any application which has a print command.