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