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