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)(11,17)(12,18)(13,16)(14,15)(19,21)(20,24)(22,23)(25,26)(27,31)(28,36)(29,34)(30,32)(33,38)(35,40)(37,39)(1,3,5,8)(2,6,4,7)(9,10)(11,12)(13,16)(14,15)(17,18)(19,20)(21,24)(22,23)(25,27,30,29)(26,31,32,34)(28,35,38,37)(33,39,36,40)(1,2,5,4)(3,6,8,7)(10,15)(11,18)(16,23)(19,24)(26,32)(31,34)(33,36)(39,40)(9,11)(10,12)(13,19)(14,18)(15,17)(16,20)(21,23)(22,24)(25,26)(27,31)(28,33)(29,34)(30,32)(35,39)(36,38)(37,40) involution — undirected(1,2,5,4)(3,6,8,7)(9,12)(10,11)(13,21)(14,17)(15,18)(16,24)(19,23)(20,22)(25,28)(26,33)(27,35)(29,37)(30,38)(31,39)(32,36)(34,40)(1,4,5,2)(3,7,8,6)(9,13,14,22)(10,16,15,23)(11,19,18,24)(12,20,17,21)(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.