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