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