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