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