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