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