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