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)(11,15)(12,19)(13,14)(16,21)(17,24)(18,22)(20,23)(25,26,31,33)(27,30,28,32)(29,34,38,40)(35,37,36,39)(2,6)(3,7)(9,10)(11,15)(12,16)(13,14)(17,23)(18,22)(19,21)(20,24)(25,27,31,28)(26,32,33,30)(29,36,38,35)(34,37,40,39)(1,3)(2,4)(5,7)(6,8)(10,14)(15,22)(16,19)(23,24)(26,33)(27,28)(34,40)(35,36) involution — undirected(1,4)(2,3)(5,8)(6,7)(9,10)(11,15)(12,16)(13,14)(17,23)(18,22)(19,21)(20,24)(25,28,31,27)(26,30,33,32)(29,36,38,35)(34,37,40,39)(9,11,13,18)(10,15,14,22)(12,20,21,17)(16,24,19,23)(25,29)(26,34)(27,35)(28,36)(30,37)(31,38)(32,39)(33,40)(9,12)(10,16)(11,17)(13,21)(14,19)(15,23)(18,20)(22,24)(25,30)(26,27)(28,33)(29,37)(31,32)(34,35)(36,40)(38,39) 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.