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