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