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