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