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