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