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