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