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