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