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