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