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