I have used conductive grease, silver ink and conductive epoxy. The grease is preferred for beginners because you can redo easily. Place only a minimal amount of the grease on the contact. To keep it in place a small piece of aluminum over the flexible part of the connector with double sided sticky tape clamped into position and then epoxied at the 2 outside edges. The clamping needs to be minimal. To redo you simply cut the epoxy. You need to use a good quality epoxy (like JB weld). If you use too much it will ooze over to the other contact points and you will have to start over.
The silver ink is probably a longer lasting solution, it can also be redone but is not as simple as the grease because no cable movement is allowed. The grease could be a problem with a "printed" connector because in theory the grease can dissolve the contact point over long periods. Circuit Works makes very good quality ink, a pen will cost about 30-40 dollars. It's real silver and thus expensive (apply with a tiny brush). I mainly use it for repairing expensive microphones and guitar pickups (reattaching wires). For that it's excellent. It can be dissolved with acetone if you need to start over. Grease was designed to reduce switch bounce in mechanical switches, equally expensive. Touchpad repair kits are also billed as "conductive ink" however in this case I would not use that because it may have a resistive quality that will kill the repair.
BTW a connector on the board would probably not work even if you could get it to fit. Solder on the cable will kill the clamping action. Trying to desolder or resolder the cable is a crap shoot and I never gamble if I can help it.
...mike