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