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