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