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