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