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)(11,21,25,32)(12,26)(13,17)(14,19)(15,20)(16,22,30,24)(18,28)(23,31,38,39)(27,34)(29,33)(35,37,40,36)(1,3,4,7)(2,5,6,8)(9,11,15,25)(10,16,20,30)(12,23,29,38)(13,24,14,22)(17,32,19,21)(18,31,34,39)(26,35,33,40)(27,36,28,37)(3,7)(5,8)(10,17)(11,22)(12,27)(13,14)(16,30)(19,20)(24,25)(26,33)(28,29)(31,35)(36,37)(39,40) involution — undirected(9,12,15,29)(10,18,20,34)(11,23,25,38)(13,28,14,27)(16,31,30,39)(17,33,19,26)(21,35,32,40)(22,36,24,37)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.