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