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