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