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