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