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