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