does anyone know where jumbo cataur is on FFVIII

Cactuar Island. It can't be accessed until you have the Ragnarok.

Edit: If you still are unsure of where that is, check out the World Map (http://www.ffonline.com/1_ff8gfx/map-world.gif)

Go to the walkthroughs and look at the map.

Actually it is possible to get to Cactuar Island using the Garden......I think, anyway take a look at this here map. (http://www.ffgon.com/ff8worldmap.shtml)