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