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