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