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