Sprinkle pork evenly with salt and pepper; coat with cooking spray. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add pork; cook 3 minutes or until browned on 1 side.
Reduce heat to medium-low; turn pork over. Cover and cook 17 minutes or until a thermometer registers 160° (slightly pink). Remove pork from pan. Cover and let stand 5 minutes.
While pork is standing, increase heat to medium-high, and add cola and bourbon to pan. Bring to a boil; cook 7 minutes or until mixture is reduced to 1/4 cup.
Spread mustard evenly on one side of bread slices. Cut pork into thin slices. Add pork slices to sauce, tossing to coat. Arrange pork slices over mustard. Spoon sauce evenly over pork.