Cook the elbow macaroni according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the cooled macaroni, diced celery, red bell pepper, red onion, and sweet pickle relish.

In a separate bowl, whisk together the mayonnaise, apple cider vinegar, Dijon mustard, salt, and black pepper until smooth.

Pour the dressing over the macaroni salad and mix until everything is well coated. Adjust seasoning if necessary.

Cover the salad and refrigerate for at least 1 hour before serving to allow the flavors to meld.