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