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