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