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