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