Once macaroni is cooked, dump in the colander to drain. Don't rinse the macaroni.. let it sit for a few minutes to cool a little. Maybe 10 minutes. Pasta will stick together. Add warm macaroni to the large bowl with mayo & vegetables, fold until combined and separated. Refrigerate for 5-6 hours or overnight. FYI - if tomatoes are extra ripe, they will become yucky after being in the fridge for over 24 hours. I would use a fairly firm tomato.