The Trailhawk comes standard with Premium Cloth / Leather Seating. There's a picture of what it looks like on another thread. The Leather Group simply completes the leather trim on the seats.
The Luxury package (only available on Limited) comes with Premium Leather, Ventilated Front Seats, Power Liftgate, Radio / Driver Seat / Exterior Mirrors with Memory & HID Headlamps.
Hope this clears things up a bit for you.
EDIT: Here's the link: 2014 Cherokee Trailhawk Interior