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)(11,14)(12,15)(13,16)(17,20)(18,21)(19,22)(23,24)(25,26)(27,34)(28,36)(29,31)(30,32)(33,38)(35,39)(37,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(10,11)(15,17)(16,18)(22,23)(25,27,30,29)(26,31,32,34)(28,35,38,37)(33,39,36,40)(2,5)(6,7)(13,21)(16,18)(19,24)(22,23)(26,32)(31,34)(33,36)(39,40) involution — undirected(9,11,14,10)(12,17,20,15)(13,18,21,16)(19,23,24,22)(25,28)(26,33)(27,35)(29,37)(30,38)(31,39)(32,36)(34,40)(1,3)(2,6)(4,8)(5,7)(9,12,14,20)(10,15,11,17)(13,19,21,24)(16,22,18,23)(25,29,30,27)(26,34,32,31)(28,37,38,35)(33,40,36,39)(1,2)(3,6)(4,5)(7,8)(9,13)(10,16)(11,18)(12,19)(14,21)(15,22)(17,23)(20,24)(25,26)(27,31)(28,33)(29,34)(30,32)(35,39)(36,38)(37,40) 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.