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