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