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