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