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