Combine first 3 ingredients in a medium bowl; toss well, and set aside.
Spread mustard evenly over 6 bread slices, and top with turkey. Top each with 1 cheese slice and 1/4 cup cabbage mixture. Top with remaining bread slices.
Spray both sides of each sandwich with cooking spray; place on a hot griddle or skillet coated with cooking spray. Cook 2 minutes on each side or until bread is lightly browned and cheese melts. Serve immediately.