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