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