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