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