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