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