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