Add the macaroni, whole eggs, water, and salt to the pressure cooking pot. Lock lid in place, select High Pressure and 5 minutes cook time.
When the cook time ends, turn off the pressure cooker and let the pressure release naturally for 5 minutes, then finish with a quick pressure release. When the valve drops, carefully remove the lid.
Remove the eggs with a slotted spoon and place them in ice cold water. Drain macaroni in a colander. When eggs are cool, peel and dice them.
In a large bowl, mix together the mayonnaise, mustard, vinegar, and sugar. Stir in the macaroni, celery, onion, and diced eggs. Add salt and pepper to taste.
Chill several hours or overnight before serving.