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