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