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