Preheat the oven to 400 degrees F. Drizzle the squash with olive oil and season with salt and pepper. Spread into an even layer on a baking sheet and roast until light golden brown and cooked through, 15 to 20 minutes.
Meanwhile, rinse the farro and place in a medium saucepot. Add 2 cups water, the cider, bay leaves and a pinch of salt and bring to a boil. Reduce to a simmer and cook until tender, 15 to 30 minutes. Drain and cool.
Whisk together the oil, vinegar, Dijon, honey and orange zest and juice in a large bowl, then season with salt and pepper. Add the farro, roasted squash, arugula, parsley, pistachios and Parmesan and toss until everything is well incorporated. Once everything is combined, taste for seasoning, adding additional salt and pepper if needed. Serve at room temperature.