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