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