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