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