One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,3)(4,7,8,6)(9,10,14,15)(11,12,17,20)(13,16,23,24)(18,19,21,22)(25,26,30,29)(27,31,34,32)(28,33,36,37)(35,38,40,39)(2,3)(6,7)(10,15)(11,17)(16,24)(18,21)(25,27)(26,31)(28,35)(29,32)(30,34)(33,38)(36,40)(37,39) involution — undirected(1,3,5,2)(4,7,8,6)(10,15)(11,17)(16,24)(18,21)(27,34)(31,32)(35,40)(38,39)(1,4,5,8)(2,6,3,7)(9,11)(10,12)(13,21)(14,17)(15,20)(16,22)(18,23)(19,24)(25,27)(26,32)(28,35)(29,31)(30,34)(33,39)(36,40)(37,38)(9,12)(10,11)(13,22)(14,20)(15,17)(16,21)(18,24)(19,23)(25,28,30,36)(26,33,29,37)(27,35,34,40)(31,38,32,39)(9,13,14,23)(10,16,15,24)(11,18,17,21)(12,19,20,22)(25,29,30,26)(27,32,34,31)(28,33,36,37)(35,38,40,39)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.