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