Add the oil, vinegar, honey and mustard to a jar with a lid. Add the shallot and season with salt and pepper. Close the jar and shake until combined. (See Cook's Note.)
Layer the peaches, pecans, Gouda and arugula in a large bowl. Pour the dressing over the top, then toss until everything is coated. Transfer to a serving bowl and serve immediately.
Cook’s Note
Dressing can be made 1 day in advance and kept refrigerated in an airtight container.