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