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