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