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