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