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