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