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