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