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