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