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