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