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)(27,35)(28,33)(29,34)(30,36)(31,37)(32,39)(38,40) 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)(28,36)(29,38)(30,34)(31,39)(33,40)(35,37)(10,17)(11,20)(12,22)(14,21)(25,28,31,29)(26,33,37,34)(27,38,39,36)(30,35,40,32)(1,3,5,4)(2,7,6,8)(9,12,15,22)(10,18,17,13)(11,19,20,24)(14,23,21,16)(25,29,31,28)(26,34,37,33)(27,38,39,36)(30,35,40,32)(9,13,15,18)(10,12,17,22)(11,21,20,14)(16,19,23,24)(25,27)(26,35)(28,38)(29,36)(30,34)(31,39)(32,37)(33,40)(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)(27,34)(28,32)(29,35)(31,40)(33,39)(37,38)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.