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