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