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