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