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