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