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