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