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