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