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