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