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