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