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