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