Bring a large pot of salted water to a boil. Add the elbow macaroni and cook 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, sliced green onions, and chopped hard-boiled eggs.

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 mixture and stir until everything is evenly coated. Chill in the refrigerator for at least 30 minutes before serving.