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