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