Glad I can repay all the help I've gotten here - This is a recipe for the dressing you were talking about, and then just make the pasta, and add whatever chopped veggies you want.
I don't have a name for it - it was given to me by a friend, and she served it poured over 2# carrots, sliced and blanched, 1 whole bermuda onion, sliced, and 1 diced green pepper. Let's call it by her name!
Holly's Salad Dressing
1 can tomato soup
1 c. oil
1 c. sugar (or less, to your taste)
3/4 c. vinegar
1 tsp. salt
1/2 tsp. pepper
1 tsp dry mustard
I remember mixing it pretty well ahead of when I wanted to use it, to let the sugar dissolve well. And when I used it on the carrot salad, I poured it over and let it set in the refrig. for a few hours before serving. Hope this helps!!