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