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