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