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