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