One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,11)(8,10)(9,12)(13,14,20,19)(15,17,22,27)(16,21,25,28)(18,26,24,23)(5,7,9,8)(6,10,12,11)(13,15)(14,17)(16,26)(18,28)(19,27)(20,22)(21,24)(23,25)(2,4)(5,7,9,8)(6,11,12,10)(13,16,20,25)(14,21,19,28)(15,24,22,18)(17,23,27,26)(5,8,9,7)(6,10,12,11)(13,17,20,27)(14,22,19,15)(16,24,25,18)(21,23,28,26)(13,18,20,24)(14,23,19,26)(15,25,22,16)(17,21,27,28)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.