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