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