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