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