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)(11,18)(12,16)(13,22)(14,17)(15,21)(19,24)(20,23)(25,26,30,31)(27,32,36,40)(28,37,39,33)(29,34,35,38)(1,3,5,4)(2,6,8,7)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(25,27,30,36)(26,32,31,40)(28,38,39,34)(29,33,35,37)(1,3,5,4)(2,7,8,6)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,28,30,39)(26,33,31,37)(27,35,36,29)(32,34,40,38)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(25,26,30,31)(27,32,36,40)(28,33,39,37)(29,38,35,34)(1,4,5,3)(2,7,8,6)(11,21)(15,18)(19,20)(23,24)(25,29)(26,34)(27,28)(30,35)(31,38)(32,37)(33,40)(36,39)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.