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