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