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