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