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