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