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