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