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