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