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