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