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