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