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