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