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