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