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