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