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