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