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