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