rathet strap down at front preferably on bottom yoke, but handlebars will do(you can bend the bars!!)
Tighten it down so it compresses the suspension a fair bit.
Same at the rear, one either side(NOT over the seat) onto seat rails or rear footrest hangers, and again compress the suspension a fair bit. This will hold it safe.
This is speaking from a lot of bike strapping down experience(main dealer for 7 years) and many many bikes carried.
Dont skimp on straps, its not worth losing the bike.