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