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