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