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