Tri-Color Pasta Salad

1 (8 ounce package) tri-color rotelle pasta
4 cups broccoli florets
1/2 red bell pepper, sliced in thin strips
4 stalks celery, cut in thin diagonal pieces
1 small can sliced ripe olives (optional)
12 ounces Italian salad dressing

Cook pasta according to package directions. Rinse well under cold water. Drain well. Add remaining ingredients. Toss and refrigerate at least overnight before serving.