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