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