In small bowl, blend olive oil, lemon juice, zest, mustard, rosemary, garlic, salt and pepper. Rub pork with olive oil mixture. Place in a resealable plastic bag and refrigerate overnight.
Place cauliflower, squash, peppers and onion in a large bowl and toss with olive oil, garlic, lemon juice and rosemary. Place in a resealable plastic bag and refrigerate overnight.
Heat oven to 450°. Brush large roasting pan with canola oil. Add pork. Arrange vegetables on a second large greased baking pan and season with salt and pepper. Place both pans in the oven and roast at 450° for 15 minutes. Reduce heat to 400° and continue roasting for 50 to 55 minutes or until pork's internal temperature registers 160° on an instant-read thermometer.
Thinly slice pork, place on platter and surround with vegetables.