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