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