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