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