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