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