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