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