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