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