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