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