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