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