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