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