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