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