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