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