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