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