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