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