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