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