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