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