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