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)(15,18)(16,19)(17,20)(21,22,24,26)(23,25,27,28)(5,7,10,8)(6,11,12,9)(13,15,16,20)(14,17,19,18)(21,23,24,27)(22,25,26,28)(6,12)(7,8)(13,14,16,19)(15,18,20,17)(21,23)(22,25)(24,27)(26,28)(1,2,3,4)(5,8,10,7)(6,11,12,9)(13,15)(14,18)(16,20)(17,19)(5,9,10,11)(6,7,12,8)(13,14)(15,18)(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.