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