OK: Please bear in mind that this is not a recipe I measure for, so please adjust to your tastes if something sounds like too much or too little. For the mayo/italian dressing mix, I just try for equal measures.
Cook pasta el dente per package instructions.
While the pasta is cooking, combine all the above ingredients in a large bowl and let set.
Drain and rinse pasta with cold water.
Add pasta to bowl containing ingredients. Stir well. Refrigerate 4 hours or overnight.