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