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