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