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