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