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