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