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