For the dressing:
Place sweet potatoes in a large pot with enough lightly salted water to cover and bring to a boil. Cook until cubes are fork tender. Drain and cool slightly.
While potatoes are cooking, make the salad dressing.
Combine the cooked sweet potato with the celery, shallot, raisins, cherries, and pecans. Pour dressing over and toss to combine. Chill four to 12 hours. Serve chilled or room temperature.