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