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