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