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