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