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