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