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