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