Geesh! And ya wonder why Klein went out of business and Trek ate them...
Okay: I agree with the others who said you can do it again - but it will take a long time of trial and error. Magnets may help. And it may break the next day.
Or you can attach some cable-guides (look around) with some housing and rebuild the cable routing. The general idea being to get the cable from shifter to BB under-shell guides. Bit of housing. Twist. Run. Done.
That's a nice Klein frame. Good blue. I'd suggest yellow housing. Good offset. Just because Klein wanted things to go through the downtube don't make it urgent.