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