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