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