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