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