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