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