Cook potatoes in boiling water 25 minutes or until potatoes are tender; drain and cool completely.
Cut potatoes into 1/2-inch cubes. Combine potatoes, onion, celery, relish, and eggs in a large bowl. Combine mayonnaise and remaining ingredients in a small bowl; stir with a whisk. Pour over the potato mixture, tossing gently to coat. Cover and refrigerate at least 8 hours.