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