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