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