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