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