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