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