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