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