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