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