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