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