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)(27,33)(28,36)(29,31)(30,35)(32,38)(34,40)(37,39)(1,2,4,5)(3,6,7,8)(9,11,14,21)(10,15,18,19)(12,22,13,20)(16,24,17,23)(27,34)(30,39)(33,40)(35,37)(2,5)(6,8)(25,27)(26,30)(28,37)(29,34)(31,39)(32,40)(33,36)(35,38) 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)(25,26)(27,30)(28,32)(29,31)(33,35)(34,39)(36,38)(37,40)(9,13,14,12)(10,17,18,16)(11,20,21,22)(15,23,19,24)(26,31)(30,39)(32,36)(33,40)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.