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