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