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