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