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