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