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