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