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