One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10,15,29,14,19,27,18)(11,16,28,31,13,26,21,34)(12,22,24,17,25,37,39,33)(20,35,40,32,23,38,36,30)(1,3,4,7)(2,5,6,8)(9,11,15,21,14,13,27,28)(10,16,29,34,19,26,18,31)(12,23,39,36,25,20,24,40)(17,30,22,35,33,32,37,38)(9,12,15,24,14,25,27,39)(10,17,18,22,19,33,29,37)(11,20,21,36,13,23,28,40)(16,30,31,35,26,32,34,38)(2,6)(5,8)(9,13,14,11)(10,16,19,26)(12,23,25,20)(15,21,27,28)(17,32,33,30)(18,34,29,31)(22,35,37,38)(24,36,39,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.