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