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