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