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