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