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