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