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