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