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