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