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