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