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