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