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)(11,18,19,23)(12,15,22,16)(14,21,24,20)(27,34)(31,39)(35,40)(36,38)(1,3,5,4)(2,6,7,8)(9,11,13,19)(10,14,17,24)(12,21,22,20)(15,18,16,23)(25,26)(27,35)(28,32)(29,33)(30,37)(31,36)(34,40)(38,39)(1,4,5,3)(2,6,7,8)(25,27,29,34)(26,31,33,39)(28,36,30,38)(32,40,37,35)(10,15)(11,19)(12,22)(14,23)(16,17)(18,24)(25,28,29,30)(26,32,33,37)(27,36,34,38)(31,40,39,35)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.