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