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