In a medium bowl, combine the cabbage, broccoli, squash, carrots, red onion, radishes and red bell pepper. Season with 3 4 teaspoon of the salt and 1 2 teaspoon of the black pepper, and mix well. Set aside.
In a small bowl, whisk together the vinegar, mustard, sugar, remaining 1/4 teaspoon salt and remaining 1 4 teaspoon pepper. While constantly whisking, add the oil in a thin, steady stream until completely incorporated. Stir in the cheese.
Pour the dressing over the vegetables and mix thoroughly. Cover with plastic wrap and refrigerate for at least 20 minutes, or as long as overnight, before serving.