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