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