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