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)(11,15,19,30)(12,22,24,35)(13,18)(14,17)(16,25,33,28)(20,36)(21,32,26,34)(23,39)(27,29)(31,38)(37,40)(3,4)(6,8)(9,11,13,26,14,19,27,21)(10,15,29,32,17,30,18,34)(12,23,25,37,24,20,28,38)(16,31,35,36,33,40,22,39)(1,3,5,4)(2,6,7,8)(11,19)(13,27)(15,30)(16,33)(18,29)(25,28)(31,40)(37,38)(1,4,5,3)(2,6,7,8)(9,12)(10,16)(11,20)(13,28)(14,24)(15,31)(17,33)(18,35)(19,23)(21,38)(22,29)(25,27)(26,37)(30,40)(32,39)(34,36)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.