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