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