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