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