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