In a large mixing bowl, combine the shredded green cabbage, shredded carrots, and shredded red cabbage.

In a separate bowl, whisk together the apple cider vinegar, granulated sugar, Dijon mustard, celery seeds, salt, and black pepper until well combined.

Slowly drizzle in the olive oil while whisking continuously to emulsify the dressing.

Pour the dressing over the cabbage mixture and toss until the vegetables are evenly coated.

Let the coleslaw sit for at least 10 minutes before serving to allow the flavors to meld.