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