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