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