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