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