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