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