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