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