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