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