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