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