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