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