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