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