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