If you ask the cab driver for a flat rate to the Royal York it should be:  $50
OR
You can call the and ask for the Concierge, and he can book you a CAR service through the limo company they deal with: $61.48


also found this:
Airport Express Shuttle Service
Pacific Western operates a 24-hour shuttle from all three terminals at Pearson International Airport to downtown Toronto, which stops at the Fairmont Royal York.

The shuttle picks up at all terminals every 20 minutes throughout the day and every 30 minutes through the night. The trip to the Fairmont Royal York takes approximately 45 minutes and costs CAD 15.50 per person, one way.

Tickets are available from the driver, or from the ticket booth located at the hotel. The shuttle pick-up area is outside the airport exit next to the baggage claim area.