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