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