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