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