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)(13,14)(15,19)(16,17)(18,20)(23,26)(24,28) involution — undirected(6,8)(10,11)(13,15,18,16)(14,19,20,17)(21,22,25,27)(23,24,26,28)(7,12)(10,11)(14,20)(15,16)(21,23)(22,24)(25,26)(27,28) involution — undirected(1,2)(3,4)(5,7)(6,10)(8,11)(9,12)(13,16,18,15)(14,17,20,19)(21,24)(22,26)(23,27)(25,28)(5,8,9,6)(7,11,12,10)(13,17)(14,15)(16,20)(18,19)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.