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