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