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