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