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