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