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