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