One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,8)(5,7)(9,10,15,14)(11,21,25,17)(12,27,31,36)(13,20,16,19)(18,32,30,29)(22,38,40,35)(23,24,26,34)(28,33,39,37)(1,3,6,2)(4,8,5,7)(9,11,15,25)(10,17,14,21)(12,28,31,39)(13,23,16,26)(18,35,30,38)(19,24,20,34)(22,32,40,29)(27,37,36,33)(9,12,15,31)(10,18,14,30)(11,22,25,40)(13,29,16,32)(17,33,21,37)(19,27,20,36)(23,39,26,28)(24,35,34,38)(1,4,6,5)(2,7,3,8)(9,13,15,16)(10,19,14,20)(11,23,25,26)(12,29,31,32)(17,24,21,34)(18,27,30,36)(22,39,40,28)(33,35,37,38)(1,5,6,4)(2,7,3,8)(9,14,15,10)(11,24,25,34)(12,30,31,18)(13,20,16,19)(17,23,21,26)(22,35,40,38)(27,29,36,32)(28,33,39,37)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.