There are a great many Sheepadoodle haircuts. It all depends on the type of coat your dog has as well as how much time and how imaginative you want to be. There are also some basic cuts. They all depend on whether your Sheepadoodle has a primarily Sheepdog or Poodle coat, however.
The Long Puppy Cut is best for Sheepdog-style coats. After a thorough bath and blow-dry, the coat is trimmed carefully down just a wee bit. The legs will look like cotton cylinders, and the rest of the body will be fluffy too. The eyes and the feet and will be invisible. The coat should bounce when the dog walks, making him look like he's floating.
The Puppy Cut allows the eyes and the feet to be seen. The coat is cut very short so it's easily maintained.
The traditional Sheepdog Cut is not so much a cut as allowing the hair to grow naturally and then shaving the dog. This was how it was done when these dogs worked the herds in their native lands. The hair grows back at about one inch a month, so keep that in mind when you shave (or trim) it.
For Poodle-type coats, the list is open-ended. Some of the basic styles are the Puppy Cut, the Teddy Bear, and the Kennel Cut. The Puppy cut is a medium length style save for the tail, which has a ball at the tip called a "pompom." The Teddy Bear on a Poodle-style coat doesn't completely hide everything, as the eyes, nose, and toenails are visible. The Kennel Cut emphasizes the top of the head and ears with long hair while the rest of the coat is trimmed short.
If your Sheepadoodle has that complete Poodle coat, there are many wild styles beyond the basic cuts: the Dutch Clip, Bikini Cut, Lamb Clip, the Continental, the Sporting Cut, Corded Coat and the English Saddle. These are detailed trims that are best described at length in books.
If you have a Sheepadoodle whose coat has both breeds' features, you can opt for a Labrador Cut. This will maintain the curly aspect of the Poodle hair but keep it short. The ears will have medium-length hair. The face can be kept somewhat long and fluffy like that of a Sheepdog.