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