It all depends on what caused the wires to short. You said you had pictures?
One cause could be that the wires were overheating and the insulation melted off causing the wires to touch and short (this should have blown a fuse). Why did the wires overheat? LOTS of causes for that. You might be able to just replace the burnt wires and your motor will be just fine (usually there's some other underlying issue that would need to be addressed first, but I've seen motors with cooked wires that were just fine. It all depends on the cause.)
Also look into the vents at the bottom of the motor and see if the windings are copper color still or if they're blackened and burnt. If the windings are cooked, scrap the motor, having it rewound will cost more than buying a new one.
Cost wise, I can't answer without physically inspecting the motor. If it were to come into the shop I work at, I would charge you $40 labor plus parts. (there's really no way I could begin to guess about parts without taking the motor apart). A true 3 horse, 2 speed motor (you need to look at the amperage of the motor to determine the true horsepower on a pool and spa motor as the pool and spa industry likes to uprate everything) would retail in my shop for about $265, so it might be worth having it looked at.
To sum that all up lol, call a local pump repair shop and ask them what their bench charges are then weigh the cost of replacement with the cost of repair and determine if it is worth it to YOU.