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