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