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