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