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)(15,16,20,19)(21,22,25,27)(23,24,28,26)(5,6,8,10)(7,9,12,11)(14,18)(16,19)(21,23,25,28)(22,26,27,24)(5,6)(7,9)(8,10)(11,12)(13,14,17,18)(15,19,20,16)(1,2)(3,4)(5,6)(7,9)(8,10)(11,12)(13,15)(14,19)(16,18)(17,20) involution — undirected(5,7)(6,9)(8,12)(10,11)(13,16,17,19)(14,15,18,20)(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.