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