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