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