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