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