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