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)(11,16)(12,15)(13,21)(14,18)(17,23)(19,20)(22,24)(25,26,31,34)(27,35,39,32)(28,29,38,40)(30,33,36,37)(1,3,5,8)(2,6,4,7)(9,11)(10,16)(12,20)(13,18)(14,21)(15,19)(17,24)(22,23)(25,27,31,39)(26,32,34,35)(28,30,38,36)(29,37,40,33)(1,2,5,4)(3,6,8,7)(10,12)(11,19)(17,21)(18,22)(25,28)(26,29)(27,36)(30,39)(31,38)(32,33)(34,40)(35,37)(9,12,15,10)(11,20,19,16)(13,21,23,17)(14,22,24,18)(25,29)(26,28)(27,37)(30,32)(31,40)(33,39)(34,38)(35,36)(9,13)(10,17)(11,18)(12,21)(14,20)(15,23)(16,24)(19,22)(25,28)(26,29)(27,30)(31,38)(32,37)(33,35)(34,40)(36,39) involution — undirected(1,4,5,2)(3,7,8,6)(9,14)(10,18)(11,21)(12,22)(13,16)(15,24)(17,19)(20,23)(25,30)(26,33)(27,38)(28,39)(29,32)(31,36)(34,37)(35,40)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.