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