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