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