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