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