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