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